GMC Sierra Complaints (2021)

671 consumer complaints on file.

#11675861July 24, 2025
ENGINE
The coolant control valve (Part # 24001355) has failed. Apparently this is the case with many vehicles and GM will not/can not get replacement parts. This should be a recall.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11675926July 24, 2025
ENGINE
P1098 Code - Coolant Control Valve on/off/on/off.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11676009July 24, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle stalled, lost motive power, with smoke came from the engine compartment. There was no warning light illuminated. The vehicle was towed to the residence. The contact attempted to start the vehicle and noticed a knocking sound coming from the engine with the check engine warning light illuminated. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The dealer was contacted and informed the contact that parts were not yet available. The dealer informed the contact that the vehicle had a Salvage Title and would not be repaired under the recall. The manufacturer was made aware of the failure, and a case was opened. The failure mileage was approximately 48,000. VIN tool confirms parts not available.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11675290July 22, 2025
POWER TRAIN
AT AROUND 60,000 MILES I HAD EXPERIENCED SHUTTERING AND JERKING IN LOW GEARS AND THE VEHICLE SHOOTS FORWARD WHEN COMING TO A COMPLETE STOP. I WAS ABLE TO TAKE THE VEHICLE IN A SHORT TIME AFTER AND I WAS TOLD BY THE DEALERSHIP THAT IT NEEDED A TRANSMISSION FLUSH. I COMPLETED THE FLUSH AND AFTER A WEEK OR TWO IT STARTED DOING IT AGAIN. I TOOK IT TO A TRANSMISSION SHOP AND THEY ADVISED IT IS THE TRANSMISSION VALVE BODY THAT IS BAD. I BELIEVE THIS STARTED HAPPENING BEFORE MY WARRANTY WAS OUT BUT DUE TO ME BRINGING IT IN AFTER THE MILEAGE THEY WOULD NOT HONOR THE WARRANTY. THIS COULD CAUSE MULTIPLE HAZARDS AT STOPS AND WHILE DRIVING. NO WARNING LAMPS OR MESSAGE HAVE EVER APPEARED.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11675155July 21, 2025
ENGINE
When I started my truck in the morning I noticed the check engine light came on and my engine fan started running really loudly. I shut my truck off and let it sit for 5 minutes and restarted it in hopes the check engine light would not appear. Unfortunately it did come back on and the engine fan began running really loudly again. I drove the truck to the nearest mechanic and you could feel the truck was trying to counter the problem by forcing me to drive it in a lower speed. After taking it to a shop to get it scanned to see what the code was. The mechanic said it was reading code P1006 three times. He said this coolant system and is why my engine fan was triggered to run really loudly. But the engine was not over heating as all other indicators showed that temps were normal. The mechanic believes it could possibly just be a faulty wire. However after talking to GM he said if it is this coolant part that needs to be replaced, it could take up to months to fix as the part is on national backorder. Doing more research, it appears others have had this same problem and GM even knew shortly after this model was released that this would happen.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11675215July 21, 2025
ENGINE, POWER TRAIN
The check engine light came on at one point. I took it to figure out why the check engine light was coming on and the scanner indicated that the NOX catalyst was below threshold. I researched it and it is a common issue. The check engine light eventually turned off after a couple of days. About 2 weeks later it came back on. I noticed as i was driving the coolant fans were running at 100% meaning that they were blowing long and hard. So I scanned it and it said that the engine coolant valve was at fault. This is also a common issue with the vehicle, particularly in the 2021 GMC Sierra 1500 3.0 Turbo Diesel. It is a faulty part and it costs thousands of dollars to replace. How can these two issues not be on a national recall by GM? They are too common and very expensive to repair. This issue is so common that now the valve is on a national back order. Meaning the parts may not be available for 30-120 days. The vehicle is not safe to drive with a bad engine coolant valve. I have now a rental car for the past 7 days while my truck sits waiting for a valve to arrive and pay thousands in repair just to drive it again.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11674474July 18, 2025
ENGINE, POWER TRAIN
wn a 2021 GMC Sierra 1500 6.2L (VIN: [XXX] ), which is now experiencing a severe misfire, engine ticking, and diagnostic code P318A. I’ve confirmed this issue is related to GM Recall N252494001 for engine connecting rod/crankshaft failure. However, I’ve been told my VIN has not yet been activated for recall repairs, and both the local dealership and GMC support have refused to escalate my case or offer assistance. This is a known safety issue, and I’m now at risk of total engine failure and significant financial loss while waiting for GM to act. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11673300July 14, 2025
ENGINE
The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The contact stated that while driving at approximately 50 MPH, there was a loud squeaking sound coming from the front driver’s side of the vehicle before the vehicle lost power. Simultaneously, the check engine warning light started blinking. The vehicle was pulled over to the side of the road and the sound became louder, before becoming a knocking sound. The vehicle was restarted, and the failure persisted. The vehicle was towed to the residence. The vehicle was not diagnosed or repaired, but a dealer stated that there was as recall associated with the VIN; however, parts were not yet available to repair the vehicle. The manufacturer was not notified of the failure. The failure mileage was approximately 128,000. VIN tool confirms parts not available.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11673334July 14, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (ENGINE AND ENGINE COOLING); however, the part to do the recall repair was not yet available. The contact stated that while the vehicle was stopped, the vehicle idled intermittently. In addition, an abnormal sound was coming from the left side of the engine. The vehicle was not diagnosed or repaired. The local dealer was not contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the issue. The failure mileage was unknown. VIN tool confirms parts not available.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11673425July 14, 2025
ENGINE
My 2021 GMC Sierra 1500 with L87 engine, covered by recall 25V274. None of my local dealers are inspecting for this recall. This truck is my daily driver and I routinely drive on interstates for my work. GM has been slow to address this major manufacturing defect and has not remedied the problem. My truck is no longer worth what is was previously and is lowering trade in or sale value. I am requesting that GM buy back my vehicle due to ongoing safety risks and loss of value.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11673218July 13, 2025
ENGINE, FUEL/PROPULSION SYSTEM
Was informed from by GM that my vehicle is involved with a recall an still hasn't been repaired
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11672973July 12, 2025
ENGINE
On Dec 27 I noticed a skip in my engine when I started the truck. I took the truck to Cronic Buick GMC on Jan 6 for an inspection. They reported to me that the engine failed.Seized up. I reported the incident to my extended warranty company Warranty Solutions. They refused to do the repair because I was late for an oil change in 2022. After 3 weeks and no cooperation I contacted GM customer service. I was assigned an agent that help initiate the engine repair . The repair was completed on April 12 (3 months after the failure). I paid $4600 out of pocket for a portion of the engine repair .
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11672996July 12, 2025
ENGINE, POWER TRAIN
What component or system failed or malfunctioned, and is it available for inspection upon request? The valvetrain system failed due to broken rocker arms, which resulted in additional internal engine damage. This failure occurred under normal driving conditions. The affected components have not yet been discarded and are available for inspection upon request.How was your safety or the safety of others put at risk? The failure caused sudden engine misfiring and knocking, reducing engine power while I was operating the vehicle. This significantly compromised acceleration and response time, especially during merging and lane changes, which could have led to an accident. Any unexpected loss of power or engine instability at highway speeds poses a serious risk to myself, passengers, and other motorists.Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The issue has been diagnosed and confirmed by an independent certified mechanic, who verified the broken rocker arms and resulting engine damage during inspection.Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? The vehicle has not yet been inspected by the manufacturer, police, or insurance representatives. Only a certified independent mechanic has inspected the failure thus far.Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? Yes. The check engine light appeared and the engine began running rough and producing a knocking sound. These symptoms occurred just prior to the confirmed failure and prompted me to stop driving the vehicle immediately and have it inspected. Given the seriousness of this issue and reports from other GMC 5.3L engine owners experiencing similar rocker arm failures, I urge the NHTSA to investigate this potential defect. It poses a real and significant safety risk.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11672673July 11, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000(Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The contact stated that while driving at approximately 60 MPH, the check engine warning illuminated and the vehicle stalled. The contact pulled to the side of the road and attempted to restart the vehicle, but the vehicle failed to restart. The vehicle was towed to the residence. The contact stated that the failure had previously occurred several times while driving. An unknown local dealer was contacted and informed the contact that the recall parts were not available. The vehicle was not diagnosed or repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was contacted and a voicemail message was left, but the manufacturer had not returned the contact's call. The failure mileage was approximately 70,000. VIN tool confirms parts not available.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11672133July 9, 2025
POWER TRAIN
The coolant control valve is faulty and is on national backorder causing months of my truck sitting in the shop. This is not an isolated issue. GM is claiming it is not covered under warranty, but the part design is clearly a serious issue.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11672165July 9, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The contact stated that the vehicle was experiencing rough idling, with the RPM fluctuating while driving. The local dealer was contacted. The vehicle was not diagnosed or repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the issue. The failure mileage was approximately 32,000. VIN tool confirms parts not available.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11672167July 9, 2025
ENGINE
Replacement part needed is COOLANT CONTROL VALVE according to diagnostics at local GM dealer service department after noting check engine light was on. YES, it is available for inspection. Told unsafe to drive as it would very likely overheat or worse. It has been in the shop for a month (as of June 11, 2025) awaiting a backordered part, which we’re told is a national backorder. No loaner vehicle available and told by service department that they have had another truck in for same problem for several months and that this problem is very common. PLEASE HELP us with getting the part needed!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11671868July 8, 2025
ENGINE AND ENGINE COOLING
See attached document for complaint.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11671925July 8, 2025
POWER TRAIN
The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 75 MPH, the vehicle jerked and downshifted to overdrive. The message "Engine Power Reduced" was displayed on the instrument panel. The driver depressed the accelerator pedal, but the vehicle failed to exceed 4 MPH. The vehicle was taken to the dealer, where it was diagnosed that the valve body failed, which caused the transmission to fail. The vehicle was repaired. While the contact was driving home after the vehicle was picked up, the vehicle jerked and hesitated. The dealer was contacted and informed the contact that if the check engine warning light becomes illuminated the vehicle could be diagnosed. After several days, the check engine warning light illuminated, and the vehicle was taken to the dealer where it was diagnosed that the shutter valve had failed and needed to be replaced. The vehicle was repaired. The contact stated that the failure persisted. The contact received NHTSA Campaign Number: 24V797000 (POWER TRAIN). The vehicle was repaired; however, the failure persisted. The manufacturer was made aware of the failure and offered the contact assistance with the transmission repair. The failure mileage was approximately 119,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11671523July 7, 2025
ENGINE
The coolant control valve on my truck is causing issues. From doing research, this is an ongoing issue with the 3.0 duramax. The part is on nationwide backorder and I cannot drive my vehicle in reduced engine power because the only way I can get to work is by taking the interstate. It is madness that GM has not issued a recall or done anything to rectify this issue. Many GMC owners are paying on vehicles that they are unable to drive which is assanine. This part needs to be readily available due to the NUMEROUS complaints that have already been submitted in regards to this part.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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